PeterO — Maybe I am reading the "Heatshield Resolution" portion of This New Ocean that you cite too literally. To me it indicates McDonnell may have ordered complete, ready-to-bolt-on, heatshields from the Brush Beryllium Company. Have you tried contacting their successor Brush-Wellman?

This New Ocean also mentioned that they forged the heatshields. I am not certain of the level of technology back in the early '60s, but if they did it right, there might have been only minor machining and drilling of the heatshield after forging.

As an aside, does anyone know if the beryllium heatshield of Liberty Bell 7 was recovered along with the spacecraft itself? It should have been sitting right underneath it, even if the landing bag had decomposed during its time on the bottom of the ocean.

SpaceAholic

Not recovered... seawater is highly corrosive to beryllium.

PeterO

When I saw LB7 in Boston in 2002, the landing bag was attached to the base of the capsule, and was displayed in the deployed position. The plaque at the open end of the bag ended with "The heat shield no longer exists. It decomposed on the ocean floor."

If I recall correctly, when LB7 was hoisted off the bottom, the remains of the heat shield were visible underneath it.

The Beryllium panels around the recovery section were also missing, with just the underlying structure and the spacers between the panels remaining.

Headshot, I noticed the reference to forging. The perimeter of the shield, where it mated to the structure of the capsule, would probably still need to be machined, but that might have been the only machining.

Headshot

Somehow I got a mental image of a 6ft diameter Fizzie tablet bubbling underneath Liberty Bell 7 on the ocean floor. Of course at that depth and temperature, the heatshield would have decomposed far more slowly.

Yes I believe there would have been just a little machining. How the landing bag was secured to the beryllium heatshield and how entire assembly was attached to the spacecraft would have dictated any additional procedures that needed to be performed on the heatshield.

Does anyone know how thick the beryllium heatshield was or how much it weighed? I would assume that it would have weighed less than the 600-pound metallic heat sink sponge mentioned in This New Ocean.

Jay Chladek

From what I can recall, the remains of the beryllium heat sink was sitting next to the capsule on the bottom of the ocean as a big gray metallic blob (its corrosion kept a low voltage current going through much of the rest of the capsule, preserving the rest of the structure from corrosion for many years). These were only used on the sub-orbital flights because if I remember right while it was determined that they would likely work for orbital flight, the amount of heat entering the cabin would char broil the occupant. Heat loads on a sub-orbital reentry aren't as high.

In addition to Freedom 7 and Liberty Bell 7, that would if we take into account the other Redstone capsules mean four total with the heat sinks?

Headshot

According to This New Ocean, NASA ordered six beryllium heat-sink shields. I assume they were used on the first four Mercury-Redstone flights. So what happened to the other two?

This New Ocean also decribes a drop test in 1959 during which the heatshield was jettisoned from the spacecraft after re-entry. It went into a falling leaf-pattern and actually impacted the test-Mercury capsule on its parachute. I believe NASA only intended to jettison the beryllium heat-sink shield at that time, so this test might account for another.

That leaves us with one "missing" beryllium heat-sink shield.

Lou Chinal

A total of six beryllium heat sink shields were forged for Project Mercury in 1959. As a result of the Big Joe test flight in Sept. 1959, it was decided to go with the ablation shield because it was much lighter.

So Peter to answer your question; they were forged first, then machined.

The beryllium would have worked, but pound for pound they were much less efficient.